377 - BET Protein Inhibitor Apabetalone Suppresses Inflammatory Hyperactivation of Monocytes From Patients With Cardiovascular Disease and Type 2 Diabetes

In Session: Advances in Immune Cell Biology

Author Block: Sylwia Wasiak, Resverlogix Corp, Calgary, AB, Canada; Kim Dzobo, Amsterdam UMC, Amsterdam, Netherlands; Brooke Rakai, Resverlogix Corp, Calgary, AB, Canada; Yannick Kaiser, Miranda Versloot, Mahnoush Bahjat, Amsterdam UMC, Amsterdam, Netherlands; Stephanie Stotz, Li Fu, Resverlogix Corp, Calgary, AB, Canada; Michael Sweeney, Jan JOHANSSON, Resverlogix Corp, San Francisco, CA; Norman Wong, Resverlogix Corp, Calgary, AB, Canada; Erik Stroes, Jeffrey Kroon, Amsterdam UMC, Amsterdam, Netherlands; Ewelina Kulikowski, Resverlogix Corp, Calgary, AB, Canada

Disclosure Block: S. Wasiak: Employment; Significant; Resverlogix. Stock Shareholder; Modest; Resverlogix. K. Dzobo: None. B. Rakai: Employment; Significant; Resverlogix. Stock Shareholder; Significant; Resverlogix. Y. Kaiser: None. M. Versloot: None. M. Bahjat: None. S. Stotz: Employment; Significant; Resverlogix. L. Fu: Employment; Modest; Resverlogix Corp. M. Sweeney: Employment; Significant; Resverlogix. J. Johansson: Employment; Significant; Resverlogix. N. Wong: Employment; Significant; Resverlogix Corp. E. Stroes: None. J. Kroon: None. E. Kulikowski: Employment; Significant; Resverlogix Corp. Stock Shareholder; Significant; Resverlogix Corp.

Introduction: Hyperactivation of the monocyte inflammatory response is partly controlled by epigenetic mechanisms and contributes to atherosclerotic plaque formation in patients with cardiovascular disease (CVD) and type 2 diabetes mellitus (DM2).

Hypothesis: Monocyte activation in DM2+CVD is regulated by bromodomain and extraterminal (BET) epigenetic readers and can be inhibited by apabetalone - a clinical stage BET inhibitor.

Methods: CD14+ monocytes from 14 DM2+CVD patients and 12 matched control subjects were treated ex vivo with 25 μM apabetalone ± 25 U/mL interferon γ (IFNγ) for 4h or 24h. Expressed genes (180) were analyzed with the Nanostring™ Innate Immunity Panel. Secreted cytokines were immunoprofiled with a Milliplex® array (42). Bioinformatics were performed with Ingenuity® Pathway Analysis (IPA®) software.

Results: Unstimulated DM2+CVD monocytes had higher IL1A, IL1B and IL8 cytokine gene expression and Toll-like receptor (TLR) 2 surface abundance than control monocytes, indicating proinflammatory activation. Ex vivo apabetalone treatment reduced IL1A and IL8 mRNA (p<0.001), as well as MCP-1, MCP-3, GRO-α, and IL-8 secretion (p<0.01), countering the pro-inflammatory activation of DM2+CVD monocytes. Further, DM2+CVD monocytes were hyperresponsive to ex vivo stimulation with IFNγ, upregulating genes within cytokine and NF-κB pathways (TNF, CCL7, CCL8, MYD88, RELA) >30% more than controls (p<0.05). Apabetalone countered IFNγ hyperresponsiveness by reducing expression of overexpressed genes by up to 30% more in DM2+CVD monocytes versus controls (p<0.01). Ex vivo apabetalone treatment also countered IFNγ induced secretion of IL-1β and TNFα in DM2+CVD monocytes (p<0.01). Consistently, IPA® analysis of immune gene signatures post IFNγ stimulation in both cohorts predicted a more prominent reduction of Toll-like receptor and cytokine pathways by apabetalone in the diseased state.

Conclusions: Monocytes isolated from DM2+CVD patients receiving standard of care therapies are in a hyperinflammatory state and hyperactivate upon IFNγ stimulation. Apabetalone treatment diminishes this proinflammatory phenotype, providing mechanistic insight into how BET protein inhibition may reduce CVD risk in DM2 patients.